1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly to a semiconductor device provided with a gate-insulated transistor.
2. Related Background Art
Conventional semiconductor devices based on Si substrate and involving MOS transistors are associated with a parasite capacitance in the source-drain pn junction, and this is an essential drawback. Although the SOI (silicon, or semiconductor on insulator) MOS transistor was invented to reduce this drawback, its commercial application has not progressed sufficiently, also from the standpoint of manufacturing cost, as the preparation of a semiconductor layer of satisfactory properties on the insulator is extremely difficult. In other words, it has not yet been developed to the practical level as a semiconductor device of a low cost, a low parasite capacitance and high-speed functioning characteristics.